Sprocket assembly

ABSTRACT

A sprocket assembly has a sliding cusp on each tooth to increase and decrease the spacing between adjacent teeth. The position of the cusp is controlled by the round and the angular orientation of the tooth.

Wnited States Patent 1191 Meier et al. Feb. 26, 1974 SPROCKET ASSEMBLY [56] References Cited [75] Inventors: Otto H. Meier, Shelbume; Douglas UNITED STATES PATENTS Tassie, George, both of 3,710,928 1/1973 Zijp 198/210 [73] Assignee: General Electric Company,

Burlington, Vt. Primary ExaminerStephen C. Bentley t A F B l' K h Filed: Oct. 1972 At orney, gent or zrm a1 in L no [21] App]. No.: 296,799 57 ABSTRACT A sprocket assembly has a sliding cusp on each tooth [52] Cl 89/33 CA, 89/33 E, 198/210 to increase and decrease the spacing between adjacent Cl. teeth The position of the cusp is controlled the {58] held of Search89/33 R, 33 BA, 33 33 CA, round and the angular orientation of the tooth.

16 Claims, 5 Drawing Figures SPROCKET ASSEMBLY The invention herein described was made in the course of or under a contract or subcontract thereunder with the Department of the Air Force.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to feeding mechanisms for automatic guns.

2. Background of the Invention In armament systems it is frequently necessary to accelerate the rounds of ammunition while conveying them from the ammunition storage system to the gun system. An armament system including a conveyor system is illustrated in U.S. Pat. No. 3,670,863 issued June 20, 1972 to OH. Meier et al. An exemplary storage system is illustrated in U.S. Pat. No. 3,720,301 issued Mar. 13, 1973 to NC. Garland et al. An exemplary gun system is illustrated in U.S. Pat. No. 3,698,283 issued Oct. 17, I972 to E. Ashley et al. The rotary feeder which receives rounds from the conveyor system and inserts them onto the rotary ammunition tray may be synchronized with the tray by means of a cam operated positive clutch and brake such as is shown in U.S. Pat. No. 3,578,118 issued May 11, 1971 toLK. Wetzel, fitted with a spring back device to absorb the inertia of a sudden stop of the feeder. In the feeder it is usually necessary to accelerate the rounds; that is, to increase the pitch or space between rounds. Conventionally this is achieved by entering the rounds into the feeder sprocket at a radius which has an annular velocity equal to the linear velocity of the conveyor system, and exiting the rounds from the same feeder sprocket at a radius which has an annular velocity equal to the annular velocity of the rotary tray. The tooth shape which is generated by the necessary entrance and exit paths of the round through the feeder, which are defined by guides external to the sprocket, requires a relatively wide space between adjacent teeth at the outer radial portion of the sprocket. This wide space tends to permit a loss of positive control or constraint of the round as it exits the sprocket.

BRIEF SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provide a sprocket assembly for a rounds accelerating feeder wherein the round is under positive control as it exits the feeder.

A further object is to provide such a sprocket as will accept the entrance of rounds in the reverse direction during a halting and spring back of the system.

A feature of this invention is the provision of a sprocket assembly having a sliding cusp on each tooth to increase and decrease the spacing between adjacent teeth. The position of the cusp is controlled by the round and the angular orientation of the tooth;

BRIEF DESCRIPTION OF THE DRAWING These and other objects, features and advantages of this invention will be apparent from the following specification thereof taken in conjunction with the accompanying drawing in which:

FIG. 1 is a side view of a sprocket assembly embodying this invention;

FIG. 2 is a side view of the sprocket of the assembly of FIG. 1;

' bly of FIG. 1; and

FIG. 5 is a front view of the sprocket of FIG. 4.

THE PREFERRED EMBODIMENT The sprocket assembly is fixed on a shaft 10 and rotates through a rounds path which is defined by an inner guide 12 and an outer guide 14. The normal direction of the movement from the conveyor into the feeder during feeding is indicated by the arrow A. The reverse direction of movement from the rotary feed tray back into the sprocket during spring back when the feeder is being halted is indicated by the arrow B.

The sprocket assembly includes three sprockets 16, each sprocket having four teeth 18, and each tooth having a sliding cusp 20. Each tooth 18 has an arcuate groove 22 into each of its two side faces 23, a tangential blind bore 24, and an arcuate cross-slot 26. Each cusp 20 has a U-shaped cross-section, as seen in FIG. 5, with a base portion 27 integral with two side portions 28, each of which side portions is integral with a respective inwardly directed foot portion 30. Each foot portion 30 rides in a respective groove 22 in the tooth. Each cusp also has a cross-hole 32 passing through the two side portions 28. A pin 34 is fixed in the cross-hole 32 and passes through the arcuate cross-slot 26 and the tangential bore 24 to retain the cusp on the tooth. A helical compression spring 36 is disposed in the blind bore 24 and is captured by and bears against the pin 34 thereby biasing the cusp centrifugally on the tooth. Each cusp also has a dorsal slot 38 in the base portion 27 extending centrifugally from the centripetal end of the cusp and terminating in an cylindrical enlargement 40. Each tooth has an additional blind bore 42 adjacent its base, in which is disposed a plunger 44 having main body 46 of a first diameter slightly less than the bore 42, a neck portion 48 of a lesser diameter and slightly less than the enlargement 40, and a tip portion 50 of a yet lesser diameter and slightly less than the width of the dorsal slot 38. The main body 46 also has a longitudinal blind bore 52. A helical compression spring 54 is disposed in the blind bore 52 and captured against the base of the blind bore 42, serving to bias the plunger centrifugally. The plunger 44 is captured in the bore 42 by the cusp. When the cusp is in its centrifugal position, limited by the cross-pin 34, the tip portion 50 rides in the slot 38. When the cusp is shifted completely against the bias of the spring 36 to its centripetal position, the neck portion 48 enters the slot enlargement 40, under the bias of the spring 54 and holds the cusp against centrifugal return. When the tip portion 50 is depressed, against the base of the spring 54, depressing the neck portion, the cusp is released, and shifts centrifugally under the bias of the spring 36.

In use, each round R approaches the sprocket in the direction A as it travels between and along the guides 12 and 14. As the round reaches the position R, it engages a centrifugally extended cusp on a tooth and progressively pushes the cusp centripetally, as it enters the valley between two adjacent teeth until the cusp reaches and is locked in its centripetal position. As the round approaches a fully seated position in the valley, it depresses the tip portion 50, to release the cusp, which snaps back to its centrifugal position to more fully encircle the round. As the round, still travelling between the guides 12 and 14, leaves the valley the cusp provides the last contact between the sprocket and the round, pushing the round further along between the guides, whereat it is picked up by the rotary feed tray.

When the feeder is halted it does not instantly decelerate to zero velocity and stop, but rather, decelerates through zero velocity, with angular travel, and subsequently springs back with reverse angular travel of about 90. During this spring back or reverse angular travel of the sprocket and the feed tray, a round will pass in the direction B from the tray into the sprocket. In this case, the round again engages and pushes the cusp centripetally until it is captured by the plunger. The round enters the valley until it is almost seated, depressing the plunger and releasing the cusp. The cusp shifts centrifugally, more fully encircling the round, so as to provide full control of that round when next the sprocket is rotated in the direction A to pass rounds to the feed tray. Further, any round which is entering a valley of the sprocket in the direction A during initial deceleration, if it has not pushed the cusp far enough centripetally to enlarge the annular entry distance between teeth to permit entry, may back away in the direction B during spring back, without being seized between the cusp and the outer guide 14. If the round has pushed th cusp far enough centripetally to enlarge the annular entry distance to permit entry, it has pushed the cusp to lock it in its full centripetal position; and may back out of the valley in the direction B during spring back without being followed by the cusp and possibly being seized between the cusp and the outer guide 14.

What is claimed is:

1. A sprocket assembly for handling articles, comprising:

a sprocket having a plurality of teeth;

each two immediately adjacent teeth defining a respective valley therebetween having a respective first, fixed, concave peripheral surface and adapted to receive an article therein;

a like plurality of cusps,

each cusp having a respective, second, concave peripheral surface and each mounted for translation on and along the first, fixed peripheral surface of a respective tooth, between a maximum centrifugal position and a maximum centripetal position.

2. A sprocket assembly according to claim 1 wherein:

each of said first peripheral surfaces has a first radius of curvature, about a respective axis; and

each of said second peripheral surfaces has said first radius of curvature about said respective axis.

3. A sprocket assembly according to claim 2 wherein:

said maximum centrifugal disposition of a respective cusp provides a minimum annular opening to the respective valley; and

said maximum centripetal disposition of a respective cusp provides a maximum annular opening to the respective valley.

4. A sprocket assembly according to claim 3 further including:

a like plurality of bias means, one for each tooth and 6 thereto mounted cusp, for biasing said cusp to said maximum centrifugal position.

5. A sprocket assembly according to claim 4 further including:

a like plurality of detent means, one for each tooth and thereto mounted cusp, for releasably retaining 5 said cusp in said maximum centripetal position.

6. A sprocket assembly according to claim 5 further including:

a plurality of fixed guides for defining a path for the articles as they are handled by said sprocket.

7. A sprocket assembly according to claim 6 wherein said guides and said sprocket are so constructed and arranged that an article passing in either direction along said path is effective to engage a cusp on a tooth to progressively translate said cusp to said maximum centripetal position and to progressively enter a respective valley.

8. A sprocket assembly according to claim 7 wherein said guides and said sprocket are so constructed and arranged that an article disposed in a valley is effective to release a respective detent to release the respective cusp to translate to said maximum centrifugal position.

9. A sprocket assembly according to claim 8 wherein:

each said detent mean includes a slot and a slot enlargement in said respective cusp;

a spring loaded plunger disposed in a bore in said respective tooth, having a tip for travel along said slot and out said enlargement to project into said valley, and a neck too large for entry into said slot but small enough to enter into and interlock with said enlargement.

10. A sprocket assembly according to claim 1, wherein:

said sprocket assembly is part of a feed of a machine gun, and

said articles are rounds of ammunition.

11. A sprocket assembly, for handling articles, comprising:

a sprocket having a plurality of teeth;

each two immediately adjacent teeth defining a respective valley therebetween, adapted to receive an article therein;

each said valley having a respective annular opening defined by the respective distal ends of said respective two teeth; and

a like plurality of cusps, each mounted for translation on and along a respective tooth, between a maximum centrifugal position providing a minimum annular opening of a respective valley and a maximum centripetal position providing a maximum annular opening of said respective valley; a like plurality of bias means, one for each tooth and thereto mounted cusp, for biasing said cusp to said maxi mum centrifugal position; and a like plurality of detent means, one for each tooth and thereto mounted cusp, for releasably retaining said cusp in said maximum centripetal position.

12. A sprocket assembly according to claim 11 further including:

a plurality of fixed guides for defining a path for the articles as they are handled by said sprocket.

13. A sprocket assembly according to claim 12 wherein said guides and said sprocket are so constructed and arranged that an article passing in either direction along said path is effective to engage a cusp LII cusp;

a spring loaded plunger disposed in a bore in said respective tooth, having a tip for travel along said slot and out said enlargement to project into said valley, and a neck too large for entry into said slot but small enough to enter into and interlock with said enlargement.

16. A sprocket assembly according to claim 11, wherein:

.said sprocket assembly is part of a feed of a machine gun, and

said articles are rounds of ammunition. 

1. A sprocket assembly for handling articles, comprising: a sprocket having a plurality of teeth; each two immediately adjacent teeth defining a respective valley therebetween having a respective first, fixed, concave peripheral surface and adapted to receive an article therein; a like plurality of cusps, each cusp having a respective, second, concave peripheral surface and each mounted for translation on and along the first, fixed peripheral surface of a respective tooth, between a maximum centrifugal position and a maximum centripetal position.
 2. A sprocket assembly according to claim 1 wherein: each of said first peripheral surfaces has a first radius of curvature, about a respective axis; and each of said second peripheral surfaces has said first radius of curvature about said respective axis.
 3. A sprocket assembly according to claim 2 wherein: said maximum centrifugal disposition of a respective cusp provides a minimum annular opening to the respective valley; and said maximum centripetal disposition of a respective cusp provides a maximum annular opening to the respective valley.
 4. A sprocket assembly according to claim 3 further including: a like plurality of bias means, one for each tooth and thereto mounted cusp, for biasing said cusp to said maximum centrifugal position.
 5. A sprocket assembly according to claim 4 further including: a like plurality of detent means, one for each tooth and thereto mounted cusp, for releasably retaining said cusp in said maximum centripetal position.
 6. A sprocket assembly according to claim 5 further including: a plurality of fixed guides for defining a path for the articles as they are handled by said sprocket.
 7. A sprocket assembly according to claim 6 wherein said guides and said sprocket are so constructed and arranged that an article passing in either direction along said path is effective to engage a cusp on a tooth to progressively translate said cusp to said maximum centripetal position and to progressively enter a respective valley.
 8. A sprocket assembly according to claim 7 wherein said guides and said sprocket are so constructed and arranged that an article disposed in a valley is effective to release a respective detent to release the respective cusp to translate to said maximum centrifugal position.
 9. A sprocket assembly according to claim 8 wherein: each said detent mean includes a slot and a slot enlargement in said respective cusp; a spring loaded plunger disposed in a bore in said respective tooth, having a tip for travel along said slot and out said enlargement to project into said valley, and a neck too large for entry into said slot but small enough to enter into and interlock with said enlargement.
 10. A sprocket assembly according to claim 1, wherein: said sprocket assembly is part of a feed of a machine gun, and said articles are rounds of ammunition.
 11. A sprocket assembly, for handling articles, comprising: a sprocket having a plurality of teeth; each two immediately adjacent teeth defining a respective valley therebetween, adapted to receive an article therein; each said valley having a respective annular opening defined by the respective distal ends of said respective two teeth; and a like plurality of cusps, each mounted for translation on and along a respective tooth, between a maximum centrifugal position providing a minimum annular opening of a respective valley and a maximum centripetal position providing a maximum annular opening of said respective valley; a like plurality of bias means, one for each tooth and thereto mounted cusp, for biasing said cusp to said maximum centrifugal position; and a like plurality of detent means, one for each tooth and thereto mounted cusp, for releasably retaining said cusp in said maximum centripetal position.
 12. A sprocket assembly according to claim 11 further including: a plurality of fixed guides for defining a path for the articles as they are handled by said sprocket.
 13. A sprocket assembly according to claim 12 wherein said guides and said sprocket are so constructed and arranged that an article passing in either direction along said path is effective to engage a cusp on a tooth to progressively translate said cusp to said maximum centripetal position and to progressively enter a respective valley.
 14. A sprocket assembly according to claim 3 wherein said guides and said sprocket are so constructed and arranged taht an article disposed in a valley is effective to release a respective detent to release the respective cusp to translate to said maximum centrifugal position.
 15. A sprocket assembly according to claim 14 wherein: each said detent means includes a slot and a slot enlargement in said respective cusp; a spring loaded plunger disposed in a bore in said respective tooth, having a tip for travel along said slot and out said enlargement to project into said valley, and a neck too large for entry into said slot but small enough to enter into and interlock with said enlargement.
 16. A sprocket assembly according to claim 11, wherein: said sprocket assembly is part of a feed of a machine gun, and said articles are rounds of ammunition. 